I have made some simulations, which revealed two very interesting details about the original Solina modulation circuit. I will not spill the beans about it yet, but I think the "classic clones" (Crumar, Boehm) probably don't have it. Hmm, the Crumar may have one of them.

Anyway, this is something I won't rely on simulation only, so I've started a huge veroboard to make some experiments. The Dual 3-phase LFO is running already, and I could omit some of the bulkier caps by using modern components.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Does that mean, the complete stringphaser requires three boards (each 27$ or so) ?

No, don't worry, certainly not 3 boards.

JH.

I've done a lot of layout work on the weekend, and the bigger part of the Solina board is done.

Good News: As it looks now, it will all fit on one board, so the price for the board will be under EUR 30.00 .

I think I have found a way to fit the 3 BBD lines close together without much interference, by applying very strict EMC design rules: Each Delay Unit (complete with clock oscillator, BBD and near-BBD filtering components) has it's own GND plane, interconnections are very short and all done as Microstrip lines.

Ok, I'll first have to try this on one prototype before I really know if it works, and if it doesn't, I have to throw the concept over and start from point zero, but that's my risk.

Your benefit will be that if it works, it will be ultra-compact, so you can even think about retrofitting existing keyboards with whis. Or put it in a very compact box.
All is relative, of course: We're still talking 160mm x 100mm here, which is big compared to the average stomp box, but small compared to the interior of a Solina keyboard's interior, and even small compared to the Boehm Phasing Rotor 78.

The (hopefully slight) downside of this concept is that I'll probably ditch the Dual-BBD "Roland Chorus" mode. I had intended to use the overhead of two boards (instead of one) to be filled with the extra circuitry for this.
But I think with half tzhe size, and practically half the cost for the PCB, that will be ok, will it?
A dual BBD chorus mode would fit on another of my planned projects better, anyway: Adding a second (entirely optional) BBD to the CE-1 clone .

That's what's going thru my head right now.

I have to see how the remaining board space is eaten up, as I procedd layouting. As I said, the complete extra control circuits for the "Roland" mode won't fit in. But maybe the wonderful String-Sound-dedicated 3-band Equalizer of the Crumar Performer will. (No promise, but likely.)

Ah, and the whole thing might run from 15V single supply, to make building a PSU easier. (YOu can still connect it to a standard +/-15V modular synth supply with the +15V unused - we only need the -15V.

And finally: I have verified the little quirks of the original Solina modulation waveshapes, that make them differ from a simple superposition of slow and fast 3-phase LFO sine waves. These will be reproduced in my version, though by slightly different means, and partly adjustable.
Filters to band limit the signal to 12kHz (Solina) will be included, too. (YOu can bypass this, though.)

All for now. Back to RIMU (my layout tool).

JH.

playing during PCB layout work:
Vangelis, Heaven and Hell
Jeff Johnson, Shadow Play
Jean-Michel Jarre, The Concerts in China_________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

I wonder, Jurgen, if one of these could be easily built into a Lambda string machine in order to replace the (crappy) built-in chorus unit?

Not sure if it would fit in there, mechanically.
Electronically, it _should_: I think the Lambda runs on +/-15V, but better double check this.

Hmm ... I own two Lambdas as well ... it's a very attractive idea indeed!

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

I was chatting with a mate yesterday and he was saying how he'd love a pedal version of the Solina chorus --- I'd not read through this thread before but had noticed it and so putting two&two together.......

But it's still completely untested. Just to give you an idea what it will look like if that design will work.

And some text about the understanding the Solina Chorus - or at least the way I think I understand it.

JH.

Now playing: Pink Floyd, Relics_________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Exciting stuff. I believe that I see a mix output and individual chorus taps as well. And connections for the three EQ points you'd mentioned? Sweet.

Yes. I decided to make th emain signal path mono, but to provide individual outputs, so everyone can mix his or her own stereo version, if needed.

Quote:

One question... No variable control for the two LFO rates? Would they sound odd at different frequencies due to the waveshaping you'd mentioned? Thanks for any response.

Just like the original. You can adjust both LFOs, but the more you deviate from the intented setting, the more your 3-phase balance will be off. Which may or may not sound interesting.

I made this decision to be as close to the original as possible, sacrificing some flexibility. For general multi-delay line experiments, there's plenty of stuff around, from BBD modules to digital FX boxes to virtual modulars.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Oh- The two LFO rates are an integral aspect of the resulting phase distribution? Not being able to surmise behaviour from schematics (or much else), I'd taken the post-LFO phase network to have been the important part.

Thanks. I'll be asking after a pair of boards when the time comes. Good work!

I feel like being among the living again.
Thank God, the virus has only hit my equilibrium system, and not my inner ear, as it did on a colleague at work.

I'll be back to work on monday, and I'll slowly pick up my PCB projects, too.

During my illness, the prototype PCBs for the Compact Clone, the Solina ensemble, and the Frequency Shifter, all arrived, one by one, from Olimex.
My wife even brought one to the hospital, to cheer me up a little.
It was about the last thing I was interested in, then, though, but I love her for doing this.

Now I'm even looking forward to go back to work - I can't just sit and do nothing for more than a couple of weeks, work-a-holic that I am.
And I'm looking forward to build and to test these PCBs.
I don't know the exact order in which these 3 projects will be available, but I think they will come in rapid succession. The Solina will probably be the first, because it relies on the availability of the TDA 1022 chips.

So, if you're interested in Solina Ensemble emulator boards, it's a good time to buy your TDA1022's now, if you haven't already.
You need 3 of these chips for one Ensemble board.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Nice work Jurgen and glad you're bouncing back. I've got to have a hospital operation at the start of Nov. which is going to keep me from working pretty much all month - luckily I get to convalesce at home, but it'll be hard to stop from doing all the day-to-day things. Its hard to put down work when it is busy and fun..

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

you can get the tda1022 also at vintageplanet.nl, but they are much more expensive there...

best wishes,

tobias.

6.95 (Euros I suppose) isn't that expensive, either, IMO.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

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